This invention relates generally to particulate sampling, and more specifically concerns an aerodynamic shield to alleviate wind-caused errors in particulate matter samplers.
Most devices which sample particulate matter (particles and drops in the size range of &lt;0.1 .mu.m to &gt;100 .mu.m diameter) in the air have an inlet which aerodynamically precludes particles which are larger than a certain size from entering the inlet. The sampler inlet design is usually such that the inertia of the larger particles prevents them from turning with the incoming airflow, or the gravitational settling speed of the larger particles is greater than the upward airflow speed into the inlet.
Such aerodynamic/inertial separation is frequently used intentionally to define the largest particles which the sampler will collect. Most inlet designs behave differently in still air than when the wind is blowing, however, and therefore the particle size cutoff of the inlet varies with the wind, often to a great degree.